Ten-year outcome of early childhood traumatic brain injury: Diffusion tensor imaging of the ventral striatum in relation to executive functioning.

PRIMARY OBJECTIVE: The long-term effects of TBI on verbal fluency and related structures, as well as the relation between cognition and structural integrity, were evaluated. It was hypothesized that the group with TBI would evidence poorer performance on cognitive measures and a decrease in structural integrity. RESEARCH DESIGN: Between a paediatric group with TBI and a group of typically-developing children, the long-term effects of traumatic brain injury were investigated in relation to both structural integrity and cognition. Common metrics for diffusion tensor imaging (DTI) were used as indicators of white matter integrity. METHODS AND PROCEDURES: Using DTI, this study examined ventral striatum (VS) integrity in 21 patients aged 10-18 years sustaining moderate-to-severe traumatic brain injury (TBI) 5-15 years earlier and 16 demographically comparable subjects. All participants completed Delis-Kaplan Executive Functioning System (D-KEFS) sub-tests. MAIN OUTCOMES AND RESULTS: The group with TBI exhibited lower fractional anisotropy (FA) and executive functioning performance and higher apparent diffusion coefficient (ADC). DTI metrics correlated with D-KEFS performance (right VS FA with Inhibition errors, right VS ADC with Letter Fluency, left VS FA and ADC with Category Switching). CONCLUSIONS: TBI affects VS integrity, even in a chronic phase, and may contribute to executive functioning deficits.

Voxel-based analysis of diffusion tensor imaging in mild traumatic brain injury in adolescents.

BACKGROUND AND PURPOSE: DTI of normal-appearing WM as evaluated by conventional MR imaging in mTBI has the potential to identify important regional abnormalities that relate to PCS. VBA was used to examine WM changes in acute mTBI. MATERIALS AND METHODS: WM was assessed between 1 and 6 days postinjury with voxel-based DTI analyses in 10 adolescent patients with mTBI and 10 age-matched control participants. In addition to the voxel-based group, analysis used to identify brain pathology across all patients with mTBI, 2 voxel-based linear regressions were performed. These analyses investigated the relation between 1) the ADC and PCS severity scores, and 2) ADC and scores on the BSI of emotional symptoms associated with mTBI. We hypothesized that frontotemporal WM changes would relate to symptoms associated with PCS and endorsed on the BSI. RESULTS: Patients with mTBI demonstrated significant reductions in ADC in several WM regions and in the left thalamus. As expected, no increases in ADC were found in any region of interest. All injury-affected regions showed decreased radial diffusivity, unchanged AD, and increased FA, which is consistent with axonal cytotoxic edema, reflective of acute injury. CONCLUSIONS: Whole-brain WM DTI measures can detect abnormalities in acute mTBI associated with PCS symptoms in adolescents.

Diffusion tensor imaging of acute mild traumatic brain injury in adolescents.

BACKGROUND: Despite normal CT imaging and neurologic functioning, many individuals report postconcussion symptoms following mild traumatic brain injury (MTBI). This dissociation has been enigmatic for clinicians and investigators. METHODS: Diffusion tensor imaging tractography of the corpus callosum was performed in 10 adolescents (14 to 19 years of age) with MTBI 1 to 6 days postinjury with Glasgow Coma Scale score of 15 and negative CT, and 10 age- and gender-equivalent uninjured controls. Subjects were administered the Rivermead Post Concussion Symptoms Questionnaire and the Brief Symptom Inventory to assess self-reported cognitive, affective, and somatic symptoms. RESULTS: The MTBI group demonstrated increased fractional anisotropy and decreased apparent diffusion coefficient and radial diffusivity, and more intense postconcussion symptoms and emotional distress compared to the control group. Increased fractional anisotropy and decreased radial diffusivity were correlated with severity of postconcussion symptoms in the MTBI group, but not in the control group. CONCLUSIONS: In adolescents with mild traumatic brain injury (MTBI) with Glasgow Coma Scale score of 15 and negative CT, diffusion tensor imaging (DTI) performed within 6 days postinjury showed increased fractional anisotropy and decreased diffusivity suggestive of cytotoxic edema. Advanced MRI-based DTI methods may enhance our understanding of the neuropathology of TBI, including MTBI. Additionally, DTI may prove more sensitive than conventional imaging methods in detecting subtle, but clinically meaningful, changes following MTBI and may be critical in refining MTBI diagnosis, prognosis, and management.